Avogadro is a Cross-Platform, Molecular builder/editor for Windows, Linux, and Mac OS X.
Avogadro is an advanced molecular editor designed for cross-platform use in computational chemistry, molecular modeling, bioinformatics, materials science, and related areas. It offers flexible rendering and a powerful plugin architecture.http://avogadro.openmolecules.net/wiki/Main_Page
* Cross-Platform: Molecular builder/editor for Windows, Linux, and Mac OS X.
* Free, Open Source: Easy to install and all source code is available under the GNU GPL.
* International: Translations into French and German, with more languages to come.
* Intuitive: Built to work easily for students and advanced researchers both.
* Fast: Supports multi-threaded rendering and computation.
* Extensible: Plugin architecture for developers, including rendering, interactive tools, commands, and Python scripts.
* Flexible: Features include Open Babel import of files, input generation for multiple computational chemistry packages, crystallography, and biomolecules.